1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Battery capability

Discussion in 'Gen 4 Prius Fuel Economy' started by I'mJp, Mar 6, 2016.

  1. I'mJp

    I'mJp Senior Member

    Joined:
    Mar 12, 2012
    628
    552
    0
    Location:
    Ma, USA
    Vehicle:
    Other Electric Vehicle
    Model:
    Three
    The Lithium-Ion battery has a spec of 207.2 volts and capacity if 3.6 ampere hours.

    So that makes it a 745.94 watt hour battery.

    MG2 has an output rating of 53 kW. I'm going to assume the motor is 100% efficient.

    Dividing, and converting to seconds, that gives the battery 50 seconds of 53kW with 100% efficiency

    That doesn't seem very long.

    How many hp does it take to keep a Prius rolling, on a smooth flat and level, say at 40 mph ?
     
    #1 I'mJp, Mar 6, 2016
  2. JimboPalmer

    JimboPalmer Tsar of all the Rushers

    Joined:
    Apr 14, 2009
    12,470
    6,871
    2
    Location:
    Greenwood MS USA
    Vehicle:
    2012 Prius v wagon
    Model:
    Three
    Typically, Toyota does not charge above 80% nor discharge below 40%.
     
    #2 JimboPalmer, Mar 6, 2016
  3. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    110,129
    50,045
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    you're way overthinking this. what are you trying to determine?
     
    #3 bisco, Mar 6, 2016
  4. Trollbait

    Trollbait It's a D&D thing

    Joined:
    Feb 7, 2006
    22,447
    11,760
    0
    Location:
    eastern Pennsylvania
    Vehicle:
    Other Non-Hybrid
    That's with the NiMH pack in order to prolong life. Li-ion can use a wider range of SOC without risking battery life.
    M/G2 is not going to be working alone with high power demands, nor will it be using the battery alone. The ICE will be running, and M/G1 supplying power to M/G2.

    I've heard 15hp to 30hp to cruise at 60mph. There is an original Insight with a fifth wheel. It is tucked up like a plane's landing gear, and it pops down when the driver turns off the ICE at speeds around 40mph. It is electric powered, and only has a 5hp motor. So the Prius will need very little energy to maintain speed at 40mph; specially if the driver can make it glide during sections.
     
    #4 Trollbait, Mar 6, 2016
  5. I'mJp

    I'mJp Senior Member

    Joined:
    Mar 12, 2012
    628
    552
    0
    Location:
    Ma, USA
    Vehicle:
    Other Electric Vehicle
    Model:
    Three
    I can cruise (flat and level) for many minutes on battery, 15 - 30 hp which is 11 - 22 kW would give 2 minutes, maybe double that for 30mph.

    My assumption of 100% efficiency is incorrect (bad assumption, but correct answer ), in that the rated 53kW of mg2 is the measured output of the motor, after losses.

    So it does make sense.



    Just checking the specs, seeing if they match my observations.

    merged

    I know that that is true for the gen 3, but I don't know the scan gauge codes for the gen 4 for the Lithium battery, so I'm unable to see what the ( possibly new ) range is.
     
    #5 I'mJp, Mar 6, 2016
  6. bwilson4web

    bwilson4web BMW i3 and Model 3

    Joined:
    Nov 25, 2005
    27,660
    15,661
    0
    Location:
    Huntsville AL
    Vehicle:
    2018 Tesla Model 3
    Model:
    Prime Plus
    1. Download the "Test Car Database" from EPA.gov (I use Google to find it.)
    2. Identify the matching car and get the three roll-down coefficients (not the dyno settings!)
      1. Target Coef A (lbf)
      2. Target Coef B (lbf/mph)
      3. Target Coef C (lbf/mph**2)
    3. Use the following formula:
      1. (mph * (Coef_A + (mph * Coef_B) + (mph * mph * Coef_C) ) / 375
    NOTE: this does not include the electrical overhead that ranges in the 450W range or about 450/745 hp.

    Bob Wilson
     
    #6 bwilson4web, Mar 6, 2016
  7. Vman455

    Vman455 Senior Member

    Joined:
    Feb 8, 2014
    534
    551
    13
    Location:
    The Middle
    Vehicle:
    2013 Prius
    Model:
    Two
    Or, using this calculator for a quick-and-dirty estimate with Gen 4 Two specs, somewhere around 6-7 horsepower, or 4-5 kW at 40mph on a level road with no wind.
     
    #7 Vman455, Mar 7, 2016
(You must log in or sign up to post here.)